This invention generally relates to the manufacture and repair of electronic devices and is especially, but not exclusively, adapted for use with printed circuit boards. More specifically, it relates to the use of special visibility materials to identify components, component placement and orientation, and/or provide information about the components and the electronic device containing the components.
Printed circuit boards are used to support a variety of electronic components and interconnect the components using copper connection paths. The outside top surface of the printed circuit board is sealed with paint or another material to prevent tarnishing of the copper paths disposed on the top surface. Labels identifying components may be silk screened onto the printed circuit board at locations adjacent the corresponding components. A color of paint is used for the labels that will contrast with the paint utilized to seal the overall top surface. For example, white labels, e.g. “IC123” identifying a specific integrated circuit, on a green background are used.
Other labels are also utilized inside the housing or chassis of an electronic device. Information such as text or graphic symbols may be contained on plastic or paper labels that are affixed to components or directly to the chassis or case of the electronic device. The information may express warnings to a user or technician, or may provide instructions relating to the servicing or repair of a component or module of the electronic device.
Computer-aided visual inspection machines are used to search for defects during the manufacture of printed circuit boards. The machines attempt to locate components that were erroneously not mounted to the printed circuit board, and components that are mounted to the printed circuit board at an incorrect location or orientation. An image of a properly assembled printed circuit board of the same type being manufactured may be stored in memory as a reference. An image of the manufactured circuit board is compared to the reference image in an attempt to locate such defects by evaluating differences in the images at various locations.
Such uses and functions give rise to needs that are discussed at the beginning of the Detailed Description section in view of the implementations of the present invention.